A single-component geopolymer cementitious material based on marine silt and shells and a method of making the same
By using alkali melting technology to disrupt the structure of marine silt and introducing calcium elements from shell powder, a single-component geopolymer cementitious material with hydraulic properties was prepared. This solved the reliance on highly reactive materials in traditional technologies and enabled the resource utilization and performance improvement of marine silt and shells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN INST OF RES & INNOVATION THE UNIV OF HONG KONG
- Filing Date
- 2026-04-07
- Publication Date
- 2026-06-05
Smart Images
Figure CN122145055A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building materials technology, specifically relating to single-component geopolymer cementitious materials and their preparation methods. Background Technology
[0002] Marine silt is sediment formed when weathered or eroded rocks are transported to the seabed by tides and currents. It is extensively extracted during human activities such as dredging, land reclamation, and fishing. Due to its high water content, soft texture, and low strength, and the presence of pollutants in some areas, marine silt cannot be directly used in engineering projects. Traditional treatment methods primarily involve dumping or landfilling at sea, resulting in resource waste and environmental pressure. Therefore, the harmless and resource-oriented treatment of marine silt is crucial for the sustainable development of the marine economy. Meanwhile, seashells, as marine waste generated from seafood processing and catering activities, have long suffered from low resource utilization rates. These natural materials, rich in calcium carbonate (≥90%), are typically disposed of as food waste in landfills, and their large accumulation exacerbates the burden on landfills.
[0003] Geopolymers are a class of cementitious materials with a three-dimensional network structure formed by the reaction of aluminosilicate raw materials with an alkaline solution. Their production process does not require limestone as a raw material, and theoretically, any solid waste rich in aluminosilicates can be used as a precursor. Their carbon footprint is lower than that of traditional silicate cement, making them a promising green and low-carbon cementitious material. However, traditional geopolymers employ a two-component preparation method, requiring the separate preparation and on-site mixing of the aluminosilicate precursor and the alkaline solution. The alkaline solution is corrosive and toxic, increasing costs and posing safety risks during storage, transportation, and disposal, thus limiting their large-scale on-site use and promotion. Therefore, developing single-component geopolymers based on solid waste (which only require the addition of water) can not only improve the resource utilization rate of solid waste but also facilitate the further promotion and application of geopolymer cementitious materials.
[0004] Existing single-component geopolymer preparation technologies typically involve ball milling a mixture of highly reactive aluminosilicate precursors (such as metakaolin and slag powder) and solid alkali activators (such as sodium silicate and sodium hydroxide). For example, publication number CN111548068B describes ball milling a mixture of pozzolanic mineral admixtures (such as fly ash and slag), recycled sand / powder mixtures, and solid alkali activators to produce single-component geopolymer recycled cement. The mechanochemical action during ball milling activates the recycled sand / powder mixture and pozzolanic mineral admixtures (such as fly ash, slag, and metakaolin) to produce geopolymer recycled cement. The recycled sand / powder mixture is then used to replace some of the fine aggregate to produce recycled geopolymer cement concrete. Publication number CN112897909A describes mixing slag and MgO powder in a mixer, adding water, mixing again, transferring the mixture to a mold, vibrating to form the final product, curing, and demolding. This type of method is not fundamentally different from traditional two-component geopolymers, but it is difficult to apply to aluminosilicate precursors with low initial activity (such as marine silt). Other studies have improved the activity of low-activity aluminosilicate precursors through high-temperature alkaline reactions. For example, Chinese patent CN115974465A describes the preparation of a one-component geopolymer by activating lead-zinc tailings with sodium hydroxide in a high-temperature alkaline fusion process, followed by mixing with slag powder and solid sodium hydroxide. Chinese patent CN103964710B describes the preparation of a one-component geopolymer by activating red mud with alkaline fusion and then mixing it with blast furnace slag powder at a ratio of 1.5:1 to 4:1. However, geopolymers prepared by these techniques still rely on the synergistic effect of adding highly reactive pozzolanic materials to achieve effective strength; their monomers themselves do not possess hydraulic properties, thus still having certain limitations.
[0005] Therefore, there is currently a lack of a method for preparing single-component geopolymers with a certain strength that uses low-original-activity aluminosilicate solid waste as a precursor and does not depend on the addition of highly active pozzolanic materials. Summary of the Invention
[0006] This invention aims to address the technical problem of existing single-component geopolymers relying on materials with high pozzolanic activity, thereby providing a single-component geopolymer cementitious material based on marine silt and shells, and its preparation method. The method of this invention uses an alkali melting technique to disrupt the aluminosilicate structure in marine silt and promote its recombination. Simultaneously, calcium from shell powder is introduced into the aluminosilicate structure for modification, ultimately yielding a geopolymer cementitious material with higher pozzolanic activity and inherent hydraulic properties, thus overcoming the limitations of traditional geopolymer preparation based on low pozzolanic activity silica-alumina precursors.
[0007] This invention relates to a single-component geopolymer cementitious material based on marine silt and shells, made from raw materials including a solid waste mixture, a solid alkali activator, and water. The solid waste mixture is composed of 60%–80% marine silt and 20%–40% shell powder by mass percentage. The solid alkali activator, calculated based on its Na₂O content, is used at 20%–30% of the solid waste mixture. When using this single-component geopolymer cementitious material, it is mixed with water at a water-cement ratio of (0.3–0.35):1 to gel.
[0008] Furthermore, single-component geopolymer cementitious materials based on marine silt and shells also include water-reducing agents.
[0009] Furthermore, the marine silt is pretreated marine silt, whose main chemical components are SiO2 and Al2O3, and the total content of (SiO2+Al2O3) is ≥70%.
[0010] Furthermore, the pretreatment method for marine silt includes the following steps:
[0011] 1) Place the marine silt blocks in a planetary mixer, add water to restore their original water content, and stir evenly to obtain a silt slurry with a certain fluidity;
[0012] 2) Pour the sludge slurry into a 2mm mesh screen for vibration filtration to remove large-particle solid impurities. Place the filtered sludge slurry in an oven at 105℃ and dry it with forced air for at least 2 days to obtain dried sludge blocks.
[0013] 3) After the dried silt blocks are crushed in a pulverizer, they are sieved through a 150μm sieve to obtain marine silt powder, thus completing the pretreatment.
[0014] Furthermore, the original water content of the marine silt was 95% by mass percentage.
[0015] Furthermore, the shell powder is pretreated shell, and its main component is CaCO3 with a mass percentage content of ≥90%.
[0016] Furthermore, shell powder is derived from recycled waste shells (such as oyster shells), and the preparation steps for shell powder are as follows:
[0017] 1) After washing the recycled waste seashells, dry them in an oven at 105℃ and then crush them to obtain dried seashell fragments.
[0018] 2) The dried shell fragments were ball-milled to obtain shell powder, which was then sieved through a 150μm sieve to obtain shell powder.
[0019] Furthermore, the dry shell fragments were ball-milled using isopropanol as a grinding aid, with a grinding ball:shell fragment:isopropanol mass ratio of 4.9:1:1, and ball-milled for 30 minutes at a speed of 650 rpm. After ball milling, the shell fragments were dried at a low temperature of 30~60℃ to prevent clumping.
[0020] Furthermore, the solid alkali activator is sodium carbonate, sodium hydroxide, or sodium silicate; among which sodium carbonate has a lower cost and relatively weaker corrosiveness, making it more suitable for large-scale application, while sodium hydroxide and sodium silicate have stronger alkalinity, which can improve the alkali fusion activation efficiency.
[0021] The above-mentioned method for preparing a single-component geopolymer cementitious material based on marine silt and shells includes the following steps:
[0022] 1. Mix 60%–80% marine silt and 20%–40% shell powder evenly by weight to obtain a solid waste mixture; then add a solid alkali activator and continue mixing evenly to obtain a mixed powder; the amount of solid alkali activator is 20%–30% of the solid waste mixture, calculated based on its Na2O content.
[0023] 2. Place the mixed powder in a muffle furnace and heat it to 650-800°C at a heating rate of 5-10°C / min for 1-2 hours. After natural cooling, the activated mixture is obtained.
[0024] 3. The activated mixture was sieved through a 150μm sieve to obtain a single-component geopolymer cementitious material based on marine silt and shells.
[0025] Furthermore, in step two, the degree of looseness and hardness of the activated mixture varies depending on the material ratio. Loose and soft activated mixtures can be directly sieved; while solidified and hard activated mixtures can be broken up by crushing or ball milling before sieving.
[0026] The above-mentioned method of using the single-component geopolymer cementitious material based on marine silt and shells includes the following steps: adding water to the single-component geopolymer cementitious material based on marine silt and shells at a water-cement ratio of (0.3~0.35):1, stirring evenly to obtain a mixture; filling the mixture into a mold or spreading it, covering it, and curing it to obtain a hardened geopolymer cementitious material.
[0027] Furthermore, when the water-cement ratio is low (0.32), a water-reducing agent is added during the mixing process of the single-component geopolymer cementitious material based on marine silt and shells with water. The amount of water-reducing agent added is calculated as 1 mL to 2 mL of water-reducing agent per 100 g of single-component geopolymer cementitious material based on marine silt and shells, which improves the flow properties.
[0028] Furthermore, the method for heat curing the mixture in the mold is as follows: cover it with sealing film, heat cure it for 3 days in a curing chamber under conditions of relative humidity >95% and temperature 80±0.5℃, demold it, and obtain the hardened geopolymer cementitious material.
[0029] Furthermore, the method for using a single-component geopolymer cementitious material based on marine silt and shells includes the following steps: mixing the single-component geopolymer cementitious material based on marine silt and shells with a cementitious material having high pozzolanic activity to obtain a mixed cementitious material; then adding water to the mixed cementitious material at a mass ratio of water to mixed cementitious material of (0.3~0.35):1, stirring evenly to obtain a mixture; filling the mixture into a mold or spreading it, covering it, and curing it to obtain a hardened geopolymer cementitious material.
[0030] Furthermore, the high pozzolanic activity cementitious material is slag powder or high-purity ore, and the addition of other high pozzolanic activity cementitious materials can further improve the mechanical properties of the material.
[0031] Marine silt contains up to 70% silica and aluminum, while seashells contain over 90% calcium. This invention utilizes the fact that marine silt and seashells can be recombined under specific process conditions to form a cementitious material network, thereby preparing a single-component geopolymer that can react with water alone to obtain strength. The advantages and beneficial effects of this invention are as follows:
[0032] 1) This invention utilizes an alkaline melting process to synergistically activate two inert and low-utilization marine solid wastes: marine silt and discarded seashells. This process disrupts the aluminosilicate crystal structure in the marine silt, allowing it to recombine with calcium from the seashells to form a more active calcium-aluminosilicate polymer. The resulting single-component geopolymer cementitious material requires only water to solidify and exhibits rapid strength development under high-temperature curing conditions.
[0033] 2) The strength of the single-component geopolymer cementitious material prepared by the present invention increases with the increase of shell powder content; when the shell powder content is 40%, the compressive strength of the obtained geopolymer cementitious material after high temperature curing for 3 days can reach 22.6 MPa, which can be used as a green low-carbon cementitious material for non-structural parts to replace traditional silicate cement.
[0034] 3) The single-component geopolymer cementitious material of the present invention can be mixed with other cementitious materials with high pozzolanic activity to improve performance. For example, when 30% of the geopolymer cementitious material is partially replaced by slag powder, the compressive strength after 3 days of high-temperature curing can be increased by more than 70%, reaching 38.7 MPa, which significantly broadens its application range.
[0035] 4) This invention uses marine waste generated in coastal areas as raw materials to prepare cementitious materials, realizing the harmless and resource-based utilization of marine silt and waste shells. Moreover, the preparation process can be extended to the building material treatment of solid waste with similar chemical composition, which is of great significance to promoting the development of green and low-carbon building materials. Attached Figure Description
[0036] Figure 1 X-ray diffraction patterns of the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 1, the calcined marine silt of Comparative Example 1, and the calcined marine silt and shell mixture of Comparative Example 2. Detailed Implementation
[0037] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.
[0038] Example 1: The preparation method of the single-component geopolymer cementitious material based on marine silt and shells in this example is carried out according to the following steps:
[0039] I. Preparation of mixed powder:
[0040] (1) Pretreatment of marine silt:
[0041] 1) Place the marine silt blocks in a planetary mixer, add water to restore its original water content to 95%, and stir evenly to obtain a silt slurry with a certain fluidity;
[0042] 2) Pour the sludge slurry into a 2mm mesh screen for vibration filtration to remove large-particle solid impurities. Place the filtered sludge slurry in an oven at 105℃ and dry it for 3 days to obtain dried sludge blocks.
[0043] 3) After the dried silt blocks are crushed in a pulverizer, they are sieved through a sieve with a pore size of 150μm to obtain marine silt powder.
[0044] (2) Preparation of seashell powder:
[0045] 1) After washing the recycled waste seashells, dry them in an oven at 105℃, then crush them to obtain dried seashell fragments;
[0046] 2) Place the dried seashell fragments into a ball mill, add isopropanol as a grinding aid, and the mass ratio of grinding balls:seashell fragments:isopropanol is 4.9:1:1. Ball mill for 30 minutes at 650 rpm. After ball milling, dry at 40℃ for 8 hours to prevent agglomeration. The resulting seashell powder is then sieved through a 150 μm sieve to obtain seashell powder.
[0047] 160 parts of marine silt and 40 parts of shell powder were mixed evenly to obtain a solid waste mixture; then 85 parts of solid sodium carbonate powder were added and mixed evenly to obtain a mixed powder; wherein the sodium carbonate, calculated based on its Na2O content, accounts for 25% of the mass of Na2O in the solid waste mixture.
[0048] 2. Place the mixed powder in a muffle furnace and calcine it at 750°C for 1 hour at a heating rate of 5°C / min. After natural cooling, the activated mixture is obtained.
[0049] 3. The activated mixture was sieved through a 150μm sieve to obtain a single-component geopolymer cementitious material based on marine silt and shells.
[0050] The hardened geopolymer cementitious material was prepared using the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 1. The specific steps are as follows: Water was added to the single-component geopolymer cementitious material based on marine silt and shells at a water-cement ratio of 0.3:1. Polycarboxylate superplasticizer was added at a ratio of 1 mL per 100 g of the single-component geopolymer cementitious material based on marine silt and shells. The mixture was stirred evenly to obtain a mixture. The mixture was filled into a mold, covered with sealing film, and heat-cured in a curing chamber for 3 days under conditions of relative humidity >95% and temperature 80±0.5℃. After demolding, the hardened geopolymer cementitious material specimen was obtained.
[0051] Example 2: The difference between this example and Example 1 is that in step one, 140 parts of marine silt and 60 parts of shell powder are mixed evenly to obtain a solid waste mixture; then 85 parts of solid sodium carbonate powder are added and mixed evenly to obtain a mixed powder; other steps and parameters are the same as in Example 1.
[0052] Hardened geopolymer cementitious materials were prepared using the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 2. The specific steps were the same as in Example 1, and hardened geopolymer cementitious material specimens were obtained.
[0053] Example 3: The difference between this example and Example 1 is that in step one, 120 parts of marine silt and 80 parts of shell powder are mixed evenly to obtain a solid waste mixture; then 85 parts of solid sodium carbonate powder are added and mixed evenly to obtain a mixed powder; other steps and parameters are the same as in Example 1.
[0054] Hardened geopolymer cementitious materials were prepared using the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3. The specific steps were the same as in Example 1, and hardened geopolymer cementitious material specimens were obtained.
[0055] Example 4: This example demonstrates the preparation of a hardened geopolymer cementitious material using the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3. The specific steps are as follows:
[0056] The single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3 was mixed with slag powder with an activity index of S95 at a mass ratio of 140:60 to obtain a mixed cementitious material. Water was then added to the mixed cementitious material at a mass ratio of 0.3:1 and stirred evenly to obtain a mixture. The mixture was placed into a mold, covered with a sealing film, and heat-cured in a curing chamber for 3 days under conditions of relative humidity >95% and temperature of 80±0.5℃. After demolding, hardened geopolymer cementitious material specimens were obtained.
[0057] Example 5: This example demonstrates the preparation of a hardened geopolymer cementitious material using the single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3. The specific steps are as follows:
[0058] The single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3 was mixed with slag powder with an activity index of S95 at a mass ratio of 120:80 to obtain a mixed cementitious material. Water was then added to the mixed cementitious material at a mass ratio of 0.3:1 and stirred evenly to obtain a mixture. The mixture was placed into a mold, covered with a sealing film, and heat-cured in a curing chamber for 3 days under conditions of relative humidity >95% and temperature of 80±0.5℃. After demolding, hardened geopolymer cementitious material specimens were obtained.
[0059] Comparative Example 1: This comparative example is the preparation of marine silt calcined at 750°C. The specific operation is as follows: The marine silt powder pretreated in step one of Example 1 is placed in a muffle furnace and heated to 750°C for 1 hour at a heating rate of 5°C / min. After natural cooling, it is sieved through a sieve with a pore size of 150μm to obtain calcined marine silt.
[0060] Comparative Example 2: This comparative example is the preparation of marine silt and shells calcined at 750°C (alkali-free melting treatment). The specific operation is as follows: The marine silt powder and shell powder pretreated in step one of Example 1 are mixed evenly to obtain a solid waste mixture; the solid waste mixture is placed in a muffle furnace and heated to 750°C for 1 hour at a heating rate of 5°C / min. After natural cooling, it is sieved through a sieve with a pore size of 150μm to obtain the calcined marine silt and shell mixture.
[0061] The single-component geopolymer cementitious material based on marine silt and shells prepared in Example 3 and the cementitious materials prepared in Comparative Examples 1 and 2 were subjected to X-ray diffraction pattern testing. The obtained X-ray diffraction patterns are as follows: Figure 1 As shown. From Figure 1It can be seen that after high-temperature calcination of marine silt alone or after high-temperature calcination of it mixed with shell powder, a large number of crystalline structures remain in the product, such as illite and albite, which are aluminosilicate minerals, quartz, and lime produced by the high-temperature decomposition of shell powder. However, when the mixture of marine silt and shell powder is activated by alkali melting, the aluminosilicate crystal structure in the marine silt is destroyed and reorganized, generating sodium aluminosilicate polymer. At the same time, calcium from the shells also participates in the network structure of the polymer, forming sodium calcium silicate polymer, which constitutes the active ingredient of the single-component geopolymer cementitious material.
[0062] The 3-day compressive strength of the single-component geopolymer cementitious material specimens prepared in Examples 1-5 was tested according to ASTM C109 standard. The 3-day compressive strength data of the specimens in Examples 1-5 are shown in Table 1.
[0063] Table 1. Strength test results of geopolymer cementitious material specimens prepared in the examples.
[0064] The test results of Examples 1-3 show that the single-component geopolymer cementitious material specimens of the present invention have hydraulic properties and can directly react with water to form strength. As the shell powder content increases from 20% to 40%, the 3d compressive strength of the specimens is significantly improved, with an increase of 135%. Examples 1-3 use sodium carbonate as an alkaline activator. During the medium-low temperature calcination process, sodium ions destroy the bridging oxygen of the aluminosilicate structure in the marine silt, causing the three-dimensional crystal structure to depolymerize into an oligomeric amorphous structure. The calcination temperature range simultaneously achieves the decomposition of calcium silicate in the shell powder, releasing calcium ions. At the microscopic level, because the ionic potential is much greater than that of sodium ions, calcium ions can directionally replace sodium ions that are bound to non-bridging oxygen and embed into the depolymerized aluminosilicate network to form a calcium-containing aluminosilicate active phase with hydraulic properties. At the same time, the replaced sodium ions can further destroy the bridging oxygen of unreacted aluminosilicates, promote the further generation of the active phase, and improve the activation efficiency. Furthermore, this low-temperature alkali-melting calcination process, with its short calcination time, not only simultaneously achieves precise depolymerization of aluminosilicate crystals and the synchronous release of calcium from shell powder, providing an optimal reaction window for calcium ions to embed into the aluminosilicate network, but also avoids the sintering deactivation of the active phase caused by ultra-high temperature calcination. The calcined mixture only needs natural cooling to retain the amorphous structure of the active phase, eliminating the need for rapid quenching. The product only needs to pass through a 150μm sieve for use, without the need for ultrafine grinding. The process steps are significantly simplified, the overall energy is greatly reduced, and it is fully suitable for large-scale industrial production.
[0065] The test results of Examples 4-5 show that when the prepared single-component geopolymer cementitious material is further mixed with slag powder with high pozzolanic activity, the mechanical properties are greatly improved. When the slag powder replacement ratio is 30%, the 3-day compressive strength can be increased by more than 70% to 38.7 MPa, which has considerable mechanical properties. This improves the application range and utilization value of single-component geopolymer cementitious materials based on marine silt and shells.
Claims
1. A single-component geopolymer cementitious material based on marine silt and shells, characterized in that, This single-component geopolymer cementitious material is made from raw materials including solid waste mixture, solid alkali activator and water; wherein the solid waste mixture is composed of 60% to 80% marine silt and 20% to 40% shell powder by mass percentage; the solid alkali activator is used at 20% to 30% of the solid waste mixture, calculated based on its Na2O content.
2. The single-component geopolymer cementitious material based on marine silt and shells according to claim 1, characterized in that, Single-component geopolymer cementitious materials based on marine silt and shells also include water-reducing agents.
3. A single-component geopolymer cementitious material based on marine silt and shells according to claim 1 or 2, characterized in that, The marine silt mentioned is pretreated marine silt, whose main chemical components are SiO2 and Al2O3, and the total content of (SiO2+Al2O3) is ≥70%.
4. The single-component geopolymer cementitious material based on marine silt and shells according to claim 3, characterized in that, The aforementioned pretreatment method for marine silt includes the following steps: 1) Place the marine silt blocks in a planetary mixer, add water to restore their original water content, and stir evenly to obtain a silt slurry with a certain fluidity; 2) Pour the sludge slurry into a 2mm mesh screen for vibration filtration to remove large-particle solid impurities. Place the filtered sludge slurry in an oven at 105℃ and dry it with forced air for at least 2 days to obtain dried sludge blocks. 3) After the dried silt blocks are crushed in a pulverizer, they are sieved through a 150μm sieve to obtain marine silt powder, thus completing the pretreatment.
5. A single-component geopolymer cementitious material based on marine silt and shells according to claim 4, characterized in that, The original water content of the marine silt was 95% by mass percentage.
6. A single-component geopolymer cementitious material based on marine silt and shells according to claim 1 or 2, characterized in that, The shell powder mentioned is pretreated shell, and its main component is CaCO3 with a mass percentage content of ≥90%.
7. A single-component geopolymer cementitious material based on marine silt and shells according to claim 6, characterized in that, The preparation steps for shell powder are as follows: 1) After washing the recycled waste seashells, dry them in an oven at 105℃ and then crush them to obtain dried seashell fragments. 2) The dried shell fragments were ball-milled to obtain shell powder, which was then sieved through a 150μm sieve to obtain shell powder.
8. A single-component geopolymer cementitious material based on marine silt and shells according to claim 1 or 2, characterized in that, The solid alkali activator is sodium carbonate, sodium hydroxide, or sodium silicate.
9. A method for preparing a single-component geopolymer cementitious material based on marine silt and shells as described in claim 1, characterized in that, The method includes the following steps:
1. Mix 60%–80% marine silt and 20%–40% shell powder evenly by weight to obtain a solid waste mixture; then add a solid alkali activator and continue mixing evenly to obtain a mixed powder; the amount of solid alkali activator is 20%–30% of the solid waste mixture, calculated based on its Na2O content.
2. Place the mixed powder in a muffle furnace and heat it to 650-800°C at a heating rate of 5-10°C / min for 1-2 hours. After natural cooling, the activated mixture is obtained.
3. The activated mixture was sieved through a 150μm sieve to obtain a single-component geopolymer cementitious material based on marine silt and shells.
10. The method of using the single-component geopolymer cementitious material based on marine silt and shells as described in claim 1, characterized in that, The method includes the following steps: adding water to a single-component geopolymer cementitious material based on marine silt and shells at a water-cement ratio of (0.3~0.35):1, stirring evenly to obtain a mixture; filling the mixture into a mold or spreading it, covering it, and curing it to obtain a hardened geopolymer cementitious material.